Work It: All-New 2020 Chevrolet Silverado HD and GMC Sierra HD Debut . . . . . . . . . . .2

Update: Phone Ringtone Plays Continuously after Incoming Call . . . . . . . . . . . . . . . . . .5

Broken Spark Plug Center Isolator . . . . . . . . . . . . . . . . .5

Spray-in Bed Liner Repairs . . . . . . .10

Transmission Valve Body Part Unique Number . . . . . . . . . . . . . . .11

Coolant Heat Shrink HOse Clamp . . . . . . . . . . . . . . . . . .12

All-New Allison 10-Speed Automatic Transmission

2020 Silverado HD and Sierra HD Powertrains

see page 8see page 6

Mid-June 2019, Volume 21, No. 12

Customer Care and Aftersales

WORK IT! All-New 2020 Chevrolet Silverado HD and GMC Sierra HD Debut

Mid-June 2019 – Page 2

CONTINUED ON PAGE 3

Bigger, stronger and more powerful than ever, the completely

new 2020 Chevrolet Silverado 2500HD/3500HD and GMC Sierra

2500HD/3500HD trucks offer increased capability and an ex-

panded range of options for customers. Compared to the current

HD models, the new trucks are larger in virtually every measure.

The HD trucks are available in 3/4-ton 2500, 1-ton 3500 single

rear wheel, and 1-ton 3500 dual rear wheel configurations with

either 2WD or 4WD.

The Silverado HD lineup includes Work Truck, Custom, LT, LTZ, and

High Country models. Sierra HD models include Sierra, SLE, SLT,

new AT4, and Denali trim lines.

The trucks offer a number of advanced features designed to

deliver for HD customers, including:

• Enhanced cooling system for vehicles equipped with the

Duramax® 6.6L diesel engine

• Available Autotrac Active 2-speed transfer case on 4WD models

• Available dual alternators on both gasoline and diesel engine

options for power needed in commercial applications

• A modular front on the trucks that enables easier mounting of

a snowplow

• Available 120 V alternating current power outlet located at

the rear of the cargo box for electrical equipment that uses a

maximum of 150 watts

• Available power up/down tailgate on Silverado HD and the in-

novative MultiPro tailgate on Sierra HD

• Available enhanced trailering system featuring a class-leading

15 camera views

POWERTRAINSThere are a choice of two powertrains: the standard all-new 6.6L

V8 gasoline engine (RPO L8T) and 6-speed 6L90 automatic trans-

mission or the available Duramax® 6.6L V8 diesel engine (RPO

L5P) and the all-new Allison 10-speed automatic transmission with

an available integrated PTO option.

The new 6.6L V8 gas engine features a cast-iron small block with

aluminum heads and direct fuel injection. It produces 401 horse-

power and 464 lb.-ft. of torque. With a longer stroke, it delivers

more than 21 percent greater torque than the previous 6.0L V8

gas engine.

The Duramax 6.6L V8 turbo-diesel engine produces 445 horse-

power and 910 lb.-ft. of torque and offers exceptional durability

with its hardened engine block that uses a deep skirt design and

light-weight aluminum cylinder heads. Combined with the new

Allison 10L1000 automatic transmission, the HD trucks have a

35,000 lb. maximum towing rating when properly equipped.

MultiPro tailgate

The HD trucks have exceptional towing capabilities.

All-New 2020 Chevrolet Silverado HD and GMC Sierra HD Debut

CONTINUED ON PAGE 4

Mid-June 2019 – Page 3

ALL-WHEEL DRIVE The available Autotrac system (RPO NQH) is a 2-speed automatic,

active transfer case. The system provides five modes: Auto 4WD,

4HI, 4LO, 2HI and Neutral. The Auto 4WD position offers the ca-

pability of an active transfer case with on-demand torque biasing

wet clutch and easy vehicle tuning through software calibrations.

The software calibrations allow for vehicle speed dependent clutch

torque levels to enhance the performance of the system.

For example, the system is calibrated to provide 0–5 lb.-ft. of

clutch torque during low speed, low engine torque operation, and

predetermined higher torque for 25 mph (40 km/h) and greater.

These calibrations prevent crow-hop and binding at low speeds

and provide higher torque biases at higher vehicle speeds in order

to enhance stability.

NEW TECHNOLOGYThe HD trucks offer an extensive number of new technologies and

safety features, including:

• Forward Collision Alert

• Following Distance Indicator

• Automatic Emergency Braking

• Front Pedestrian Braking

• Front and Rear Park Assist

• Rear Cross Traffic Alert

• Lane Departure Warning

• Safety Alert Seat

• HD Surround Vision

• Head-Up Display

Many of the vehicle controls, including some safety features, the

available diesel exhaust brake, and available Integrated Trailer

Brake Controller can be operated or turned on/off using the

switchbank and other controls on the center of the instrument

panel.

TRAILERING SYSTEMThe available Advanced Trailering System (Silverado HD) and

ProGrade Trailering System (Sierra HD) features up to15 camera

views (up to two accessory cameras can be installed), including

high-definition Surround Vision and other unique views, such as a

transparent trailer view feature to help see behind the trailer when

towing and a hitch view camera that aids in connecting a trailer

to the vehicle. To check the available camera views when in Drive,

touch the Camera icon on the infotainment screen and select the

desired view. Touch X on the screen to exit the view.

In addition to the trailering system, other trailer technologies and

hardware that are available on the new HD trucks include:

• Auto Electric Park Brake – automatically applies the parking

brake to help maintain truck position when hitching

• New Park Grade Hold Assist – enhances hill hold by using

braking effort at each wheel for an extended period of time

Autotrac system controls

Many vehicle controls are easily accessed on the center switchbank.

Mid-June 2019 – Page 4

• Integrated Trailer Brake Controller – works with the trailer

profile in the Trailering App to recall a specified trailer’s most

recent gain setting

• Tow/Haul Mode – remains engaged on the next key-on cycle,

for up to four hours; includes a reminder the feature is engaged

• Hill Start Assist and Hill Descent Control

• Trailer Sway Control

• Auto Grade Braking and Diesel Exhaust Braking

• Digital Variable Steering Assist – dynamically optimizes power

steering according to driving scenarios, including trailering, and

enables road pull compensation and other features

• Trailering Info Label – located on the driver’s door jamb with

the truck’s specific trailering information, including curb weight,

GVWR, GCWR, maximum payload, maximum tongue weight

and rear GAWR.

New, larger door-mounted trailering mirrors are standard on all

2500HD and 3500HD models. The trailering mirrors have been

redesigned with improved perimeter lighting. The mirrors extend

and retract using a four-bar-link system for smooth operation,

whether done manually or with the available power extension

controls. A new forward-facing spot lamp on each mirror shines

light at about a 45-degree angle, providing illumination on the job

site or campsite. There also are side-view cameras mounted within

the mirror housings, and when equipped, mirror-mounted puddle

lamps and two rearward-facing spot lamps.

To extend the trailering mirrors manually, grasp the mirror hous-

ing firmly and pull back in one motion, arching slightly toward

the rear of the vehicle. To return the mirror to its original position,

reverse the motion.

ACTION CENTERA Technical Assistance Center (TAC) Action Center (U.S.) has been

established for product feedback on the 2020 Silverado HD and

Sierra HD. Any vehicle issues that warrant prompt and immediate

attention should be reported to TAC, not just concerns requiring

technical assistance. Any concerns will be answered by a Silverado

HD/Sierra HD specialist. The Action Center is connected directly to

TAC, Engineering, and the assembly plant in order to address any

product concerns.

To report a concern, create a TAC Case using the Dealer Case

Management (DCM) system. Refer to Bulletin #08-00-89-014E for

more information about using the DCM system. The Silverado HD/

Sierra HD specialist will provide any diagnostic direction as needed

through the DCM. Contact TAC if needed once a case has been

started.

For additional information on the new 2020 Silverado HD and

Sierra HD, refer to Bulletin #19-NA-091.

Thanks to Kevin Minor and Sherman Dixon

The trailer mirrors can be extended for enhanced visibility.

Available transparent trailer view (requires accessory camera)

All-New 2020 Chevrolet Silverado HD and GMC Sierra HD Debut

Mid-June 2019 – Page 5

The ringtone on a mobile phone may sound continuously through

the vehicle speakers after an incoming call on some 2018-2019

Sonic, Trax, Terrain; and 2019 Blazer, Camaro, Colorado, Equi-

nox, Malibu, Silverado 1500, Sierra 1500, and Canyon models

equipped with the Infotainment 3 Low system (RPO IOR). The

continuous ringtone, which will sound for the remainder of the

ignition cycle, is found only with Android phones running OS 9.0

and that have the Android Auto app installed. The phone must be

paired via Bluetooth or tethered to the infotainment system using

Android Auto. The ringtone condition is caused by an integration

concern between the vehicle and the phone.

The customer’s phone software can be updated in order to correct

the ringtone condition. Remind customers to always update their

phones with the latest software available.

TIP: The phone software is released by the individual cellular car-

riers, which may cause the release dates and software versions to

vary slightly between cellular carriers. Once the phone update is

installed, no further action is necessary. Installation of the update

resolves this condition without having to perform the previous

work-around to modify the phone settings.

UPDATE THE PHONETo identify if the phone needs to be updated:

1. On the phone, select Settings > About Phone > Software Infor-

mation.

2. View the Base-

band version of

the software.

The last four

characters of the

Baseband version

should be one of

the following or

greater: CSC1,

CSC2, CSC7, or

CSC8.

The 4th character

from the end (C)

indicates the year

released. The 3rd

character from

the end (S) indi-

cates the month.

If these characters

listed under Base-

band version on the phone are less than the version listed above,

instruct the customer to update the phone.

For additional information, refer to #PIT5655B.

Thanks to Jeremy Richardson

Update: Phone Ringtone Plays Continuously after Incoming Call

Check the Baseband version of the software to determine if a phone

update is necessary.

Broken Spark Plug Center IsolatorAn engine misfire condition and DTC P0300 (Engine Misfire Detected)

may be found on some 2016-2019 Cruze models with the 1.4L engine

(RPO LE2); 2016-2019 Malibu models with the 1.5L engine (RPO LFV);

2016-2019 Spark models with the 1.4L engine (RPO LV7); 2016-2019

Volt models with the 1.5L engine (RPO L3A); and 2018-2019 Equinox

and Terrain models with the 1.5L engine (RPO LYX).

If there is an engine misfire or engine misfire-related DTC set, remove

the spark plugs from the engine and inspect for a broken center insula-

tor by inverting the spark plug. Once the spark plug has been inverted,

if the center insulator is broken, it will slide down the center electrode.

If center insulator is broken, replace all four spark plugs. Clear any

DTCs and evaluate engine performance.

Thanks to Robert Halas Broken center insulator covering the center electrode

Mid-June 2019 – Page 6

2020 Silverado HD and Sierra HD Powertrains

CONTINUED ON PAGE 7

The all-new 2020 Silverado HD and Sierra HD trucks offer two

powertrain choices: the all-new 6.6L V8 gasoline engine (RPO L8T)

paired with the 6-speed 6L90 automatic transmission (RPO MYD)

and the Duramax 6.6L V8 diesel engine (RPO L5P) mated to the

all-new Allison 10L1000 10-speed automatic transmission (RPO

MGM, MGU).

6.6L V8 GASOLINE ENGINEThe new 6.6L V8 gas engine uses a cast-iron small block with

aluminum heads, a forged steel crankshaft, forged powder-metal

connecting rods and additional high-strength components for

long-term durability. It generates 401 horsepower and 464 lb.-ft.

of torque — that’s 22 percent more torque and up to 18 percent

more towing capability when compared to the previous 6.0L V8

gas engine. With variable valve timing and spark ignited direct

injection (SIDI), it delivers precise fuel control that enables a

compression ratio of 10.75:1 for enhanced performance and fuel

efficiency.

The fuel system is an electronic returnless on-demand design that

reduces the internal temperature of the fuel tank by not returning

hot fuel from the engine to the fuel tank for lower evaporative

emissions. The electric turbine-style fuel pump attaches to the fuel

tank fuel pump module inside the fuel tank. The high pressure

fuel pump, fuel rail pressure, fuel injection timing, and injection

duration are controlled by the Engine Control Module (ECM).

The fuel pressure sensor is a serviceable 5 V, 3-pin device that is

located on the fuel feed line forward of the fuel tank.

The engine oil capacity with filter is 8 quarts (7.6 liters) and

dexos® 1 Approved – GEN 2 viscosity grade 5W-30 engine oil is

required.

The 6.6L gas engine also will be offered with dual alternators to

support the electrical needs for trailering, snowplowing and other

jobs.

DURAMAX 6.6L V8 DIESEL ENGINEMaximum power and towing capability in new HD trucks comes

from the proven Duramax 6.6L V8 turbo-diesel engine that

produces 445 horsepower and 910 lb.-ft. of torque. Its towing

capability is increased up to 52 percent with driveline improve-

ments including the addition of the all-new Allison 10L1000 10-

speed automatic transmission.

The hardened engine block uses a deep skirt design for increased

rigidity while the light-weight aluminum cylinder heads quickly

dissipate heat. The four valves per cylinder and ports have a high

swirl design to improve combustion.

The engine uses eight ceramic glow plugs that enable greater

efficiency through higher temperature capability and faster pre-

heating time. Ceramic glow plugs are considered one-time-use

because they are much more sensitive to damage than conven-

6.6L V8 gasoline engine

Duramax 6.6L V8 diesel engine

Mid-June 2019 – Page 7

tional glow plugs. Anytime a ceramic glow plug is removed from

the cylinder head, install a new glow plug. Clean the glow plug

bore of any carbon build-up before installing the new plug.

The engine oil capacity with filter is 10 quarts (9.5 liters) and

15W-40 viscosity grade engine oil with an API CJ-4 or CK-4

designation is required. In extreme cold weather below 0°F

(–18°C), use 5W-40 engine oil.

The diesel exhaust aftertreatment system is designed to reduce

the levels of hydrocarbons (HC), carbon monoxide (CO), oxides of

nitrogen (NOx), and particulate matter (PM) in the engine exhaust

gases. Reducing these pollutants to acceptable levels is achieved

using a Diesel Oxidation Catalyst (DOC), Select Catalyst Reduction

(SCR), and a Diesel Particulate Filter (DPF). Proper operation of the

diesel exhaust aftertreatment system requires the use of ultra-low

sulfur diesel (ULSD) fuel and Diesel Exhaust Fluid (DEF).

The DEF tank is relocated farther back on the HD truck’s frame

and out of sight from the exterior. The DEF filler inlet is located

next to the fuel filler for convenient filling. An electronic gauge

display on the Driver Information Center (DIC) indicates the DEF

fluid level. In addition, as the DEF level becomes low, warning are

displayed on the DIC. As the tank nears empty, vehicle speed will

be limited in a series of steps. At least 2 gallons (7.57 L) of DEF

must be added to release the speed limitation.

AFTER-RUN COOLINGThe new diesel after-run feature on the Duramax engine was

specifically engineering for use following a demanding towing

situation. The after-run system allows the engine to keep run-

ning for up to 15 minutes to allow it to cool down by running the

larger 28-inch (71 cm) diameter, variable speed fan and circulating

coolant. The system notifies the driver that required engine cool-

ing is needed when the transmission is shifted to Park by display-

ing an alert on the Driver Information Center (DIC) that states to

keep the engine running for cool down. If the message is ignored

and the vehicle is turned off and exited, the truck will restart on

its own via remote start mode for cool-down. The truck will turn

off when the engine reaches an acceptable temperature.

ENGINE COOLANT HEATERThe engine coolant heater outlet has been moved to a more

convenient, external location on the driver’s side of the truck, in-

tegrated into the front bumper, which eliminates the need for a

cord to hang out of the grille or to open the hood for plug-in. The

coolant heater operates using 110 V alternating current from an

external power source and is designed to warm the coolant in the

engine block area for improved starting in weather conditions that

are colder than 0°F (−18°C). Vehicles with an engine block heater

should be plugged in at least four hours before starting. An inter-

nal thermostat in the plug-end of the cord may exist, which will

prevent engine coolant heater operation at temperatures warmer

than 0°F (−18°C). The coolant heater also helps reduce fuel con-

sumption when a cold engine is warming up. The unit is equipped

with a detachable AC power cord. A weather shield on the cord is

provided to protect the plug when not in use.

For additional information on the new 2020 Silverado HD and

Sierra HD, refer to Bulletin #19-NA-091.

Thanks to Kevin Minor and Sherman Dixon

DEF filler is located next to the fuel filler. The engine coolant heater outlet is integrated into the front bumper.

Mid-June 2019 – Page 8

CONTINUED ON PAGE 9

The all-new Allison 10-speed 10L1000 automatic transmission

(RPO MGM, MGU) available on 2020 Silverado HD and Sierra HD

models equipped with the 6.6L Duramax diesel engine combines

enhanced performance, fuel economy, and operational flexibil-

ity with an industry-leading reputation for reliability. Designed

for high-performance and low-maintenance, the new 10-speed

transmission — the first-ever offered in the heavy-duty pickup

segment — has been tested and validated in partnership with

Allison Transmission and, combined with the proven Duramax 6.6L

diesel engine, offers a powertrain combi-

nation that provides superior power

delivery and productivity.

TRANSMISSION ARCHITECTURE The transmission has 10 speed ratios that are generated using

four simple planetary gear sets, two brake clutches, and four

rotating clutches. The on-axis transmission architecture uses a

squashed torque converter, an off-axis pump and four close-

coupled gear sets. The four rotating clutches are located forward

of the gear sets to minimize the length of oil feeds that provide

for enhanced shift response. There are different variants of the

transmission, all based on torque capacity. Architecture is common

between the variants, and component differences are primarily

related to size.

The transmission architecture features a case with an integral bell

housing for enhanced powertrain stiffness. A unique pump drive

design allows for off-axis packaging very low in the transmission.

The pump is a variable vane type, which effectively allows for two

pumps in the packaging size of one. This design and packaging

strategy provides for ideal oil routing to the controls system with

the pump located in the valve body itself.

The 4-element torque converter contains a pump, a turbine, a

pressure plate splined to the turbine, and a stator assembly. The

torque converter acts as a fluid coupling to smoothly transmit

All-New Allison 10-Speed Automatic

Transmission

10L1000 automatic transmission

Transmission case with integral bell housing

4-element torque converter

Mid-June 2019 – Page 9

power from the engine to the transmission. It also hydraulically

provides additional torque multiplication when required. The pres-

sure plate, when applied, provides a mechanical direct drive cou-

pling of the engine to the transmission.

The hydraulic system primarily consists of an off-axis gear-driven

variable vane-type pump next to the valve body, and two control

valve body assemblies. The pump maintains the working pressures

needed to stroke the clutch pistons that apply or release the fric-

tion components, which consist of six multiple disc clutches. The

multiple disc clutches deliver 11 different gear ratios, 10 forward

and one reverse, through the gear sets.

TRANSMISSION CONTROL SOLENOID VALVESThe Transmission Control Module (TCM), which is externally

mounted, uses three speed sensor signals for enhanced shift

response and accuracy .The TCM receives and monitors various

electronic sensor inputs and uses this information to shift the

transmission at the optimum time.

The 10-speed transmission could contain a maximum of nine in-

dividual solenoids — RPO dependent — installed in various bore

locations on the lower control valve body assembly and internal

transmission case. Eight of the nine solenoid valves are used to

control pressure regulation and direction of transmission fluid. The

one on/off solenoid valve is only used to direct transmission fluid.

The normal operating current range for these solenoid valves

is between 0–1.2 amps. If the TCM detects an electrical circuit

malfunction or excessive current flow, the TCM will turn off the

high-side driver to that solenoid and set a DTC.

Transmission control solenoid valves 1–8 are pressure regulating

valves. Each solenoid valve is tested after assembly to determine

the output fluid pressure at certain electrical values, applied to

the coil winding, and is referred to as solenoid current/pressure

data points. The current versus pressure data points are saved and

assigned a file number, which is marked on the solenoid valve

housing end or on the valve body itself. The solenoid perfor-

mance data file is programmed and stored in the vehicle’s TCM as

well as stored on the Techline Information System (TIS) website.

Replacing any of the following components require the TCM to be

programmed with either the new or existing solenoid valve perfor-

mance data, depending on what component is replaced.

• Transmission assembly – program the TCM with the new

data file stored on the TIS web site for all pressure regulating

solenoid valves.

• Lower control valve body assembly with solenoid valves – pro-

gram the TCM with the new data file stored on the TIS web site

for all pressure regulating solenoid valves.

• Transmission Control Module – program the TCM with the

existing data file stored on the TIS web site for all pressure

regulating solenoid valves.

• One or more solenoids – program the TCM with the new

data file stored on the TIS web site for all pressure regulating

solenoid valves that were replaced.

POWER TAKE-OFFThe available all-new factory-integrated, engine-driven Power

Take-Off (PTO) eliminates the need for an aftermarket unit.

Exclusively offered with the 10-speed transmission (RPO MGU) on

select diesel models, it’s the first fully integrated PTO system in the

HD truck segment, with the PTO’s drive gear operated via chain to

direct engine power. And because it is engine-driven rather than

turbine-driven, the PTO can be used while the vehicle is idling.

A button inside the cab enables the PTO, and a mode selector

allows adjustment of load and torque output.

Thanks to Kevin Minor and Sherman Dixon

The PTO’s drive gear is operated via a chain (#2) to direct engine power.

Mid-June 2019 – Page 10

CONTINUED ON PAGE 11

A spray-in bed liner (RPO CGN, PDL) is available on 2013-2014

Silverado HD 2500/3500, Sierra HD 2500/3500; 2014 Silverado

1500, Sierra 1500; and 2015-2019 Colorado, Silverado, Canyon

and Sierra models. The bed liner is applied directly to the truck

bed at the factory, which creates a bonding coating that pre-

vents water, dirt, dust and other contaminants from affecting the

painted metal surface of the truck bed.

The bed liner has a black finish that resists degradation from

exposure to sunlight, chemicals, and other environmental factors

while providing a textured surface that helps prevent slippage

or movement of items stored in the bed. The coating also resists

scratches, dents and dings that would damage a regular painted

surface.

Because the bed liner material is sprayed on evenly, any variation

in the bed, such as seam sealer or spot welds in the sheet metal,

will show underneath the spray-on coating. The coating does not

completely fill in these variations.

Spray-in Bed Liner Repairs

TIP: The spray-in bed liner has been specifically designed and

tested for GM trucks. The spray-in bed liner was not designed for

use with the GM Accessory Cargo Management System offers on

2010 and prior models.

The bed liner also features several drain holes that provide open-

ings for drainage in the bed.

BED LINER CAREThe shine and luster of the bed liner can fade from oxidation,

road dirt, heavy-duty hauling and hard water stains. To help keep

the bed liner looking and performing well, it is recommended

that it be cleaned at the same time and manner as the rest of the

vehicle by washing using a mild detergent and rinsing the liner.

Automatic car wash residue may leave a white film, which can be

removed with normal washing and brushing if needed.

Do not use silicone-based protection products to clean the bed

liner as they may reduce the effectiveness of the slip resistant

texture. Silicone-based materials may also degrade the spray-in

bed liner surface. A specific silicone-free bed liner conditioner is

available through your GM dealership.

To restore the original appearance, wash the bed liner with a mild

detergent. Once the liner is dry, apply the silicone-free bed liner

conditioner and let dry. The conditioner will spray on blue, but

will dry clear.

The finish resists degradation and provides a textured surface.

Spot weld under the bed liner

Drain holes in the bed liner

Mid-June 2019 – Page 11

All repair information, parts and/or facilities that can perform the

repairs are listed on the website.

Small repairs (a repair 1.5 in. (40 mm) in diameter or less) can be

completed using a repair kit that can be ordered at gmbedliner-

repair.com. Select the Order Parts link.

The dealership or an authorized repair center can complete this

repair. It is for small areas of damage and uses a twin pack of

repair material and dual cartridge caulk gun along with a pattern

patch.

For additional information about spray-in bed liner repairs, refer

to the latest version of Bulletin #12-08-51-002.

Thanks to Tom Renno

REPAIRSBed liner repairs should be handled similar to other body repairs

and sublet to an appropriate vendor or performed by the dealer-

ship, if proper equipment and skill set are available, including all

warranty repairs, New Vehicle Damage claims, customer pay and

collision repairs.

Repairs to the spray-in bed liner fall into small or large categories.

The size of the damage will determine how the repair procedure

should be performed. Any damage to the underlying sheet metal

must be repaired, including corrosion protection, prior to repair-

ing the bed liner material.

Most large repairs will likely be performed by an approved

Ultimate Linings authorized dealer network facility and submitted

as a sublet repair if it is a warranty claim or New Vehicle Damage

claim. These facilities can be found at gmbedlinerrepair.com.

gmbedlinerrepair.com website

Small bed liner repair

The 10L80 and 10L90 10-speed automatic transmissions (RPO MHS, MHW, MF6, MGL,

MQB) available on 2017-2019 Camaro, 2018-2019 Escalade, Tahoe, Yukon Denali, 2019

CT6, Silverado 1500, Sierra 1500, and Suburban models feature a Part Unique Number that

may contain the letter O or the number zero.

If the transmission valve body is replaced, the software may not accept the Part Unique

Number (PUN) during the characterization procedure if the PUN is incorrect. Keep in mind

that the PUN may contain the letter O as well as the number 0 (zero).

The PUN must be entered correctly during programming. Be sure to enter the PUN accu-

rately and to take notice of the difference between the letter O and the number zero.

Thanks to Terry Neuendorf

Transmission Valve Body Part Unique Number

1. Number 0 2. Letter O

GM TechLink is published for all GM retail technicians and service consultants to provide timely information to help increase know ledge about GM products and improve the performance of the service department.

Publisher: John Meade GM Customer Care and Aftersales

Editor: Lisa G. Scott GM Customer Care and Aftersales

Technical Editor: Mark Spencer mspencer@gpstrategies.com

Production Manager: Marie Meredith

Creative Design: 5by5 Design LLC dkelly@5by5dzign.com

Write to: TechLink PO Box 500, Troy, MI 48007-0500

GM TechLink on the Web: GM GlobalConnect

General Motors service tips are intended for use by professional technicians, not a “do-it-yourselfer.” T hey are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the information applies to your vehicle or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information. Inclusion in this publication is not necessarily an endorsement of the individual or the company.Copyright© 2019 General Motors. All rights reserved.

Mid-June 2019 – Page 12

Coolant Heat Shrink Hose Clamp

The 2019 Silverado 4500HD/5500HD/6500HD is equipped with the 6.6L

Duramax diesel engine (RPO L5D). The engine uses heat shrink clamps to

secure the engine coolant hoses.

If a coolant heat shrink clamp needs to be replace for a coolant leak or a

service repair, it may be difficult to reinstall a heat shrink clamp to seal the

coolant hose in some locations. Where possible, a heat shrink clamp should

be used in all places where they are installed.

If there is a location underhood where it is difficult to get enough acces-

sibility in order to use a heat gun to properly install the heat shrink clamp,

use a hose clamp (part number 1518389C1) and torque the clamp to the

proper specification (9-11 Nm or 79–97 lb. in.).

When installing a heat shrink clamp:

1. Slide the heat shrink clamp fully over the fitting bead and as close to the

hose end as possible.

2. Turn heat shrink clamp so the writing on the clamp is fully visible.

3. Set the heat gun to the high setting.

4. Using the heat gun in a constant steady motion, apply heat to as much

of the heat shrink clamp as possible.

5. Continue heating the clamp until the printed information on the heat

shrink clamp turns gray, indicating that enough heat has been applied.

6. Stop heating the clamp.

7. Check the quality of the seal by trying to turn the hose by hand. Neither

the hose nor heat shrink clamp should turn.

Thanks to Bob Briedis

Coolant heat shrink hose clamp

Heat shrink clamp on the radiator outlet hose